Saunders J R, Grinsted J
J Bacteriol. 1972 Nov;112(2):690-6. doi: 10.1128/jb.112.2.690-696.1972.
RP4, an R factor derived from Pseudomonas aeruginosa S8 and specifying resistance to carbenicillin, neomycin, kanamycin, and tetracycline, could be isolated as an extrachromosomal satellite of covalently closed circular DNA (CCC-DNA) of molecular weight about 62 million and of buoyant density 1.719 g/cm(3) (60% guanine plus cytosine). When RP4 was compared by hybridization with RP1, an R factor originating in another strain of P. aeruginosa, it was shown that RP4 contains most, if not all, of the base sequences of RP1, and also additional sequences not found in RP1.
RP4是一种从铜绿假单胞菌S8中获得的R因子，它对羧苄青霉素、新霉素、卡那霉素和四环素具有抗性，可作为分子量约6200万、浮力密度为1.719克/立方厘米（鸟嘌呤加胞嘧啶含量为60%）的共价闭合环状DNA（CCC-DNA）的染色体外卫星分子进行分离。当通过杂交将RP4与源自另一株铜绿假单胞菌的R因子RP1进行比较时，发现RP4即使不包含RP1的全部碱基序列，也包含了大部分，并且还含有RP1中未发现的额外序列。
